Enum value of TRUE breaks schema (#244)

Author: jimkyndemeyer

gen/com/intellij/lang/jsgraphql/GraphQLParser.java

@@ -100,7 +100,7 @@ operationType ::= 'query' | 'mutation' | 'subscription'
 
 private description ::= quotedString
 
-enumValue ::= !('true' | 'false' | 'null') identifier {methods=[nameIdentifier="identifier"] extends=value}
+enumValue ::= identifier {methods=[nameIdentifier="identifier"] extends=value}
 
 arrayValue::= '[' arrayValueElement* ']' {pin=1 extends=value}
 

src/grammars/GraphQLParser.bnf

@@ -175,6 +175,15 @@ public void annotate(@NotNull PsiElement psiElement, @NotNull AnnotationHolder a
             }
         }
 
+        // valid enum value names according to spec
+        if (psiElement instanceof GraphQLEnumValue) {
+            final GraphQLIdentifier nameIdentifier = ((GraphQLEnumValue) psiElement).getNameIdentifier();
+            final String enumValueName = nameIdentifier.getText();
+            if ("true".equals(enumValueName) || "false".equals(enumValueName) || "null".equals(enumValueName)) {
+                createErrorAnnotation(annotationHolder, nameIdentifier, "Enum values can not be named \"" + enumValueName + "\"");
+            }
+        }
+
         // validation using graphql-java
         final AnnotationSession session = annotationHolder.getCurrentAnnotationSession();
         final PsiFile containingFile = psiElement.getContainingFile();